Childers Batteries – October 2025
The evolution of the humble solar panel is amazing when you think about where it has come in a relatively short space of time. We have gone from the old 190 Watt panels to massive 700 Watt panels for commercial applications. Solar panels are the real engine room of your system and sizing the panels and matching the strings to the correct solar regulator can be a very tricky business.
Typically, these days we go with 440 Watt panels for 99% of on or off grid installs and 510 Watt panels for commercial installs. So are bigger panels the answer? Well, Yeah/No. I know right, it’s such an Australian thing to say. The number one rule in solar panels and regulators is that you must NEVER OVER VOLT the regulator. You can over current (in other words put too much solar on) by about 30%, but you must never over voltage the regulator. Solar panels simply catch photons from the sun (little light particles) and turn them into an electrical current. The stronger the sun, the stronger the current. The solar regulator’s job is to convert that energy into a nicer version for the batteries. If I take a caravan for example, most 12V panels are usually between 18V and 24V. A 12 volt battery does not like such high voltages so it is the solar regulator’s job to reshape the power into a more compatible power for the batteries. House systems can be up to 1000V (which is ridiculous) so you could imagine what would happen when you feed that into a 48V battery…Just BANG!!!
The biggest solar trap we see is when people try and put house panels on 12V battery systems in caravans and cabins. That massive conversion really reduces the amount of solar you can use at 12V. For example, a Victron 100/30 Solar reg (which means it can take 100V and 30 Amps) will only accept 440W of panels at 12V but the same regulator will accept 880W at 24V. I don’t have enough space (and I doubt anyone cares) to explain the reasons why…but just to say that you need to be on your toes when designing your solar system.
I would always say that adding more panels is a good thing. It’s all dandy when the sun is out but when it’s overcast…the more panels the better. So adding a couple of extra panels to the string can make a massive difference. And especially with the price of panels being so cheap.
Also remember to keep the panels clean and free from moss. We have a local legend who is in her 80’s and we fitted some new lead batteries to her aging system. I pointed out that her panels were covered in moss and I gave her the details for a local solar guy who could come and test the panels and give them a clean for her. Months later I spoke to her to see how she got on. She said “Oh, they are much better now. I got up on the roof with a plastic scraper and cleaned them all off”. Seriously, what a trooper!!!
If you need help sizing your solar panels and regulator…drop in for a Chit Chat and we can guide you as needed.
Oh and remember as we approach the active fire season to always check under your panels to make sure leaves of cane trash hasn’t built up…it only takes one ember on a windy day!!
Megsy Out.
Written by Jason Marshall.
Chitchat Newspaper. October 2025.